Indications, contraindications, and pitfalls of patellofemoral arthroplasty.

Recently, there has been renewed interest in patellofemoral arthroplasty, with the development of newer designs that have produced more consistent outcomes; however, historically, the reported results of this procedure have varied widely1. The purpose of this article is to analyze trends in the published results of this procedure, to identify critical factors contributing to the success or failure of these operations, and to relate the initial lessons that we have learned from our six-year clinical experience with the Avon patellofemoral arthroplasty (Stryker Orthopaedics, Mahwah, New Jersey). Indications, contraindications, mid-term follow-up results, and ways to avoid pitfalls are delineated. It is our intent that, with this information, surgeons will have a more critical view when considering patellofemoral arthroplasty for salvage in patients with isolated patellofemoral arthritis or advanced, refractory, symptomatic patellofemoral chondromalacia. In 1955, McKeever described the first successful attempt at prosthetic salvage in patients with symptomatic isolated patellofemoral degenerative disease2. His technique involved only patellar resurfacing with a Vitallium shell (Fig. 1), and it has been abandoned because of concerns about potential trochlear wear. In 1979, the era of patellofemoral arthroplasty began when Blazina et al. reported the results of the use of the Richards I/II prosthesis (Smith-Nephew Richards, Memphis, Tennessee)3. Refinements and development of other prostheses followed. These procedures have achieved variable success, with rates of satisfactory outcomes ranging from 42% to 92%1,4. Some of these prosthetic designs have been associated with problems. For example, as first noted by Blazina et al., medial impingement of the patellar prosthesis in flexion in excess of 90° continues to be a common design-related concern that has been implicated in the etiology of recurrent postoperative effusion3 (Fig. 2). Despite the existing problems, most of these devices continue to have their advocates; however, …